Electrical stimulus circuit

Abstract

The present invention relates to a remotely triggered improved electrical stimulus circuit to be worn by cattle that is lightweight and can store voltage lower than what is to be supplied to an animal. Known cattle electrical stimulus collars may be heavy, use a lot of energy, and not supply a consistent electrical stimulus. The present electrical stimulus circuit utilizes feedback loops to allow the use of high tolerance lightweight capacitors, and/or cool down periods to utilize a highly inefficient transformer running fully saturated.

1 . An electrical stimulus system for a wearable device configured to be worn by an animal, the system configured to apply an electrical stimulus to an animal, the system comprising:
 a. an energy source;   b. an electrode pair;   c. an electrical stimulus circuit operable to generate the electrical stimulus from the energy source and provide the generated stimulus to the electrode pair, and comprising one or more capacitors configured to store energy for an output transformer; and   d. a controller configured to operate the electrical stimulus circuit when required,   wherein the electrical stimulus circuit is configured to generate the electrical stimulus from operation of the output transformer characterised by operational parameters representing a substantially saturated state.   
     
     
         2 . The system as claimed in  claim 1 , wherein the output transformer operationally generates the electrical stimulus as an output pulse having an output pulse energy, wherein operation of the output transformer is characterised by between 30% and 80% of the output pulse energy is generated by the output transformer operating in a saturated state. 
     
     
         3 . The system as claimed in  claim 1 , wherein the output transformer operationally generates the electrical stimulus as an output pulse having an output pulse energy, wherein operation of the output transformer is characterised by the output pulse energy being between 20% and 50% of a pulse energy input into to the output transformer. 
     
     
         4 . The system as claimed in  claim 1 , wherein the output transformer operationally generates the electrical stimulus with an output pulse having an output pulse energy, wherein the output pulse energy is one or more of:
 between 0.1 and 0.15 J and a pulse energy input from the capacitors into the output transformer is about 0.5 J; and   substantially 0.15 J and an input pulse energy input from the capacitors into the output transformer is at least 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9 or 0.95 J.   
     
     
         5 . The system as claimed in  claim 1 , wherein the output transformer operationally generates the electrical stimulus as an output pulse having an output pulse width, wherein operation of the output transformer in the substantially saturated state is characterised by one of:
 at least 50% of the output pulse width is generated by the output transformer operating with an efficiency of 50% or less; and   at least 55, 60, 65, 70, 75, 80, 85, 90 or 95% of the output pulse width is generated by the output transformer operating with an efficiency of 50% or less.   
     
     
         6 . The system as claimed in  claim 1 , wherein the output transformer comprises a second transformer and the system further comprises a first transformer, and the controller is configured to:
 control the connection of the energy source to the first transformer during a first interval;   control the connection of the capacitor circuit to the first transformer during the first interval to store energy from the first transformer;   control the connection of the capacitor circuit to the second/output transformer during a second interval; and   control the connection of the electrode pair to the second transformer during the second interval to realize operation of the substantially saturated state.   
     
     
         7 . The system as claimed in  claim 6 , wherein the connection of at least the second interval comprises a pulsed connection to thereby elicit flyback operation in the second transformer. 
     
     
         8 . The system as claimed in  claim 6 , wherein the output transformer is configured to receive energy stored by the capacitor circuit. 
     
     
         9 . The system as claimed in  claim 6 , wherein the output transformer is configured to step up the energy stored by the capacitor circuit to a range between 400V and 30 kV. 
     
     
         10 . The system as claimed in  claim 6 , wherein the boost transformer increases the energy source volts to a range between 400 volts and 800 volts. 
     
     
         11 . The system as claimed in  claim 6 , wherein the boost transformer operates in the linear region of saturation. 
     
     
         12 . The system as claimed in  claim 6 , wherein the controller is configured to switch energy from the energy source to the first transformer, between generated stimulus, to charge the capacitor circuit. 
     
     
         13 . The system as claimed in  claim 1 , wherein the energy source supplies between 20 and 40 watts, and/or 3 and 5 volts, or about 4.2 volts. 
     
     
         14 . The system as claimed in  claim 1 , wherein the wearable device is an animal wearable collar comprising a housing configured to support at least the output transformer and the capacitor. 
     
     
         15 . An electrical stimulus system for a wearable device configured to be worn by an animal, the system configured to apply an electrical stimulus, having an output pulse energy, to an animal, the system comprising:
 a. an energy source;   b. an electrode pair;   c. an electrical stimulus circuit comprising one or capacitors configured to receive energy directly or indirectly from the energy source, and store and provide input energy to an output transformer, the electrical stimulus circuit operable to generate output pulse energy from the input pulse energy to the electrode pair to generate the electrical stimulus, and,   d. a controller configured to operate the electrical stimulus circuit when required; and   wherein the output transformer is configured to output between 30% and 80% of the output pulse energy in a saturated state, and the output pulse energy is between 20% and 50% of the pulse energy input into the output transformer.   
     
     
         16 . The system as claimed in  claim 15 , wherein the energy source is less than 5 volts, and the output pulse energy is greater than 0.1 joules. 
     
     
         17 . The system as claimed in  claim 15 , wherein the output pulse voltage is greater than 1.5 kilovolts. 
     
     
         18 . The system as claimed in  claim 15 , wherein the output transformer has an energy density around 13.9 mj/cm 3  and/or around 7.7 mj/g.